1. Field of the Invention
This invention relates to an image display apparatus and an X-ray diagnostic apparatus, and more particularly to an improvement in an endovascular treatment method, especially an improvement in a method of drawing a wire route projected line for passing through a complete obstruction and determining an observation direction in endovascular treatment.
2. Description of the Related Art
There has been an endovascular treatment method. In recent years, the endovascular treatment method has suddenly been popularized since such a device as a guide wire (hereinafter, referred to as a wire) or a catheter is inserted into a blood vessel and moved forward to treat the affected area with the device, which makes the method less invasive than and as effective as an abdominal operation. In the future, use of computed tomography images (CT images) will become mainstream in developing a treatment plan.
Computed tomography (CT) images are volume (3D) data obtained by taking images and reconstructing the images with a CT scanner which collects X-ray projected images through an angle of 360 degrees around the human body and reconstructs the images into two-dimensional tomographic images. The volume data enables a cross-sectional image of a blood vessel to be observed and therefore is very useful.
For example, in a treatment for a complete obstruction where a blood vessel is clogged completely, the operator creates blood vessel cross-sectional images 2 from the CT volume data as shown in FIG. 1. In the blood vessel cross-sectional images 2, the operator observes a hard part (such as a calcified part) 6 and a soft part (such as a soft plaque) 8 in the clogged part of a blood vessel 4 and determines on which side of the blood vessel 4 the wire should be moved forward. From FIG. 1, it is seen that a fibrotic part 12 on the left side of the vessel center line 10 is a part through which the wire is easily passed. One publicly-known document is, for example, Morton J. Kern, “Cardiac Catheterization Handbook” Igaku-Shoin Ltd.
When the operator who has developed a treatment plan using the aforementioned blood vessel cross-sectional images enters a catheter room for actual treatment, images obtained in real time from the X-ray imaging system in the catheter room are blood vessel projected images, not blood vessel cross-sectional images. For this reason, the operator has to convert the three-dimensional positional relationship between the currently seen projected image and the planned cross-sectional images in the operator's head and convert the treatment plan from the planned blood vessel cross-sectional images into the blood vessel projected image right in front of the operator's eyes.
However, the conversion work in the operator's head is a great burden on the operator, particularly when the operator is still a bit new. There is a risk of a new operator being irresolute or making a mistake.